And I'm David Greene. It has been an astonishing overnight and morning in and around the city of Boston. Some of you may be hearing this after following this story all morning. Some of you, especially in the western United States, might be just waking up.

Here is what we know: There have been major breaks in the investigation of Monday's Boston Marathon bombings. Overnight, authorities shot and killed one suspect. Another suspect is on the run. A third - considered to be an accomplice - is in custody. In Boston, residents are in lockdown, being told to remain in their homes, only answering the door if it is a clearly identified police officer. That is also the case in the surrounding communities of Boston.

The two suspects connected to the bombings have been identified as brothers from the Russian Republic of Chechnya. The younger of the two brothers has been identified as Dzhokhar Tsarnaev, 19 years old, and he is still at large.

INSKEEP: And let's try to learn a little bit more about him. In the last half-hour or so, we heard from a young man named Zolan Young, who went to school with Dzhokhar Tsarnaev. It turns out that Zolan Young's aunt is Robin Young, a familiar name to public radio listeners because she is the host of HERE & NOW, a program produced by WBUR in Boston. She's on the line.

Robin, good morning.

ROBIN YOUNG, BYLINE: Good - well, it's just been a horrible morning. But...

INSKEEP: Yes, indeed, indeed. I understand that you also know Dzhokhar Tsarnaev, this 19-year-old who's described as still at large.

YOUNG: Well, I have to tell you, we had no idea yesterday when we saw the first images that came out from the FBI. But it's the 7-11 images - as you know, there was an armed robbery at a 7-11 right after that, a shootout at nearby MIT, an MIT officer killed. They had an image from the 7-11, and then you knew it was him. And you talk to my nephew - this has been stunning. I had the prom party for that class in my backyard, dozens of kids, they - careful kids. They rented a trolley. You know, they had their tuxes and their dresses. They rented a trolley so they could all drive safely.

And Dzhokhar was just - you know, the light of the party, a beautiful, beautiful boy with curly black hair, you know, light attitude. The only thing I remember, Steve, that stood out - and when I talked to my nephew this morning, he said: You know, Aunt Robin, he was the one in the car. And he, at one point, they...

INSKEEP: What does that mean, the one in the car?

YOUNG: Well, he got in a car, and he gunned it and raced backwards down the street. Now, of course - you know, down a one-way street in our crowded, New England little neighborhood. And I said to Zolan, does that mean anything? And he said, no. He says he was kind of goofy, fun. He talked to him, I'm sure he told, they texted just a little while ago, no sign of this. No sign of this.

And, Steve, you know, I know that's such a cliche, but it has to be said. And the other thing these kids really want said: This school, Cambridge Rindge and Latin, you know, right in Cambridge, right there - you know, Harvard, MIT, Tufts. There's tons of private schools around, but this is the public school. They've got 45 different languages in that school. None of them would have cared if somebody was from Chechnya.

INSKEEP: Well, let me ask about that very thing, Robin Young, because Dzhokhar and Tamerlan - his older brother, who was believed killed overnight - are being described as Chechnyans. We're asking lots of questions about that connection. Did they ever talk about the region of Russia that they came from?

YOUNG: Zolan said the young - he didn't know the older boy, who was 26, much older.

INSKEEP: Right, right.

YOUNG: And, you know, I know you don't like to dabble in speculation, but there is speculation, since he is the one who is said to have traveled back, potentially, to Russia...

INSKEEP: The older brother. But the younger brother, you had no sense that he was...

YOUNG: No sense. In fact, you know, Zolan said - as I was saying, 45 different languages, one of the most diverse schools in the country, so proud of that. They had a white class president, a beautiful girl who defiantly knocked off - you know, said she wouldn't go to some of the top schools in the country that accepted her because they weren't diverse enough. They were so proud of their diversity. They had Hindi, Buddhist, Muslim. You just didn't - it wasn't something that stood out.

INSKEEP: Well, Robin Young, stay with us, because I want to bring in another voice to this conversation. NPR's Tom Gjelten has been covering this story throughout the night and throughout the morning. We get a very different picture from police of this young man, Dzhokhar Tsarnaev, who is the man who is believed to be still at large.

And Tom, for those that are just waking up - particularly on the West Coast, but anybody waking up and hearing our coverage, here - would you remind us how we got here in the last 24 hours or so?

TOM GJELTEN, BYLINE: Well, Steve, Dzhokhar Tsarnaev is the man that the police identified yesterday as suspect number two, and they had video images, photo images of what now appears, in retrospect, to in fact match the images we now have of Dzhokhar. They had images of him at the bombing site, and they claim that he was the one they were looking for and were holding responsible for the bombings this week at the Boston Marathon.

And then, as Robin says, last night, he is alleged to have held up a 7-11 convenience store in Cambridge. Subsequent to that, he and his brother are alleged to have shot and killed an MIT police officer, stolen his cruiser, and then later carjacked a Mercedes SUV, and then engaged in a very violent confrontation with police, in which an MBTA policeman was shot and critically wounded.

INSKEEP: An astonishing series of events there, and in the end of that, you have one man dead. You have one man believed to be still alive, and police searching for him in Watertown, Massachusetts, among other places.

Robin Young is still on the line with us. And Robin, I want to ask about an explosive subject, here, but the dots that have put on the board require us to ask this question. We've been told that these young men have a connection to Chechnya, where there have been radical movements, particularly Islamic radical movements. We've been told by a WBUR reporter that according to neighbors, the young man's parents were observant Muslims. We don't know anything about the religion or - let's stress - the motivations of these young men. And even if we knew their religion, we wouldn't know that that was a motivation. But do you know anything about the religious beliefs of this teenager, Dzhokhar Tsarnaev, whom you met?

YOUNG: Well, and knew - and again, knew him as teen, and for years. So let me just address one thing: People have said earlier this morning, maybe two or three o'clock, we were hearing reports that they'd only been in this country for a year. Well, that's not true. We've known Dzhokhar since he was much younger. He went through all of high school with him. And as I said, Steve, it's - I can't say it enough. He never talked about his faith. Zolan wasn't aware of his faith. But there...

INSKEEP: Your nephew, who was friends with him, wasn't aware of his faith. OK.

YOUNG: Yeah. My nephew, who was friendly with him and - very friendly. Would call him one of his best friends - never talked about faith or religion, never talked about politics. And he told me this morning, he's the opposite of that. The last time they texted, it was about the Super Bowl game. Just - and in this particular school, you would not have at all noticed or been quizzical about someone whose family was from Chechnya and was Muslim. There's a mosque on the major thoroughfare near his home, right across from the Whole Foods. You just would not - it wouldn't have been even a curiosity.

INSKEEP: In any event, he didn't push it into people's faces.

YOUNG: Nothing.

INSKEEP: OK. Well, Robin, thanks very much.

YOUNG: Oh, it's just heartbreaking, Steve. Thank you.

INSKEEP: Robin Young is the host of WBUR's HERE & NOW, and was an acquaintance of Dzhokhar Tsarnaev, who is believed to still be at large in Watertown, Massachusetts. His older brother, Tamerlan Tsarnaev, was killed by police overnight - that is according to the authorities - both of them described as suspects in the Boston Marathon bombings.

NPR's Tom Gjelten is still with us. And Tom, in a few seconds, can you talk us through some questions that law enforcement officials and other officials surely would be asking next? Not only as they pursue this subject, but try to chase leads overseas.

GJELTEN: Well, that's exactly right. First of all, of course, they do have to pursue this subject. And as our correspondent Carrie Johnson pointed out earlier, they want him to come in alive, because they want to know what he knows, and they want to talk to him. And it would be really tragic in many cases - in many senses, if he were killed in the - during some kind of operation to arrest him.

There is a third person who is in custody. We don't know if he was an accomplice. We don't know why he is in custody. He was suspected to be holding explosives. That's why he was stripped naked when he was taken. We just don't know where this is going.

INSKEEP: OK, thanks very much. That's NPR's Tom Gjelten, bringing us up to date. There is still a search underway for one of the two suspects in the bombing. You're listening to MORNING EDITION, from NPR News. Transcript provided by NPR, Copyright NPR.